Re: [nfs-utils PATCH] Don't allow junction tests to trigger automounts

[Jeff Layton <jlayton@kernel.org>]

On Tue, 2022-12-13 at 11:01 -0500, Jeff Layton wrote:
> JianHong reported some strange behavior with automounts on an nfs server
> without an explicit pseudoroot. When clients issued a readdir in the
> pseudoroot, automounted directories that were not yet mounted would show
> up even if they weren't exported, though the clients wouldn't be able to
> do anything with them.
> 
> The issue was that triggering the automount on a directory would cause
> the mountd upcall to time out, which would cause nfsd to include the
> automounted dentry in the readdir response. Eventually, the automount
> would work and report that it wasn't exported and subsequent attempts to
> access the dentry would (properly) fail.
> 
> We never want mountd to trigger an automount. The kernel should do that
> if it wants to use it. Change the junction checks to do an O_PATH open
> and use fstatat with AT_NO_AUTOMOUNT.
> 
> Cc: Chuck Lever <chuck.lever@oracle.com>
> Link: https://bugzilla.redhat.com/show_bug.cgi?id=2148353
> Reported-by: JianHong Yin <jiyin@redhat.com>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>  support/junction/junction.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 

Ping? Steve, can you comment on (or merge) this patch?

Thanks,
-- 
Jeff Layton <jlayton@kernel.org>